Here’s a neat trick for Calendar (a.k.a. iCal).
In Tip 268 of Mac Kung Fu 2nd Edition I explain a hack that extends week view in Calendar to any number of days — 14 (two weeks), or 10 days, or whatever you want.
However, it transpires there’s a much easier way of viewing between 2-7 days at a time. This can be useful if you want to see how your schedule looks for the next three days, for example.
First, switch to Day view using the button on the main toolbar. Then hold down Option (Alt) and Command, and hit the number relating to how many days you want to see. For example, to see three days, you’d hit Option+Command+3.
To switch to seeing four days, you must return to day view (that’s important!), and then type Option+Command+4.
This isn’t permanent, so if you switch to any other view mode, then switch back to week view, you’ll see seven days again (or however many days you’ve set in Preferences for week view).